1. Field of the Invention
This invention relates to digital audio disc players, and more particularly, to a digital audio disc player with a slow-playback mode and a reverse slow-playback mode.
2. Description of the Prior Art
In a digital audio disc player, a spindle motor rotates a digital audio disc usually in a counter-clockwise direction, as viewed from the underside of the disc. A pickup device is located opposite the disc on its underside and continuously moves from the inner periphery to the outer periphery. A transporting mechanism, such as a worm gear and a motor, is used to move the pickup device with respect to the disc. A frequency generator is provided to detect the rotational velocity of the spindle motor. The detected signal from the frequency generator is applied to a control circuit for the motor so that the motor rotates by a predetermined amount at each revolution of the disc. The signal indicating the position of the pickup device is supplied to a control circuit for the spindle motor to control it so that the disc rotates at a constant linear velocity.
In a digital audio disc, data indicating the playing time of each recorded musical selection can be inserted before the actual commencement of the respective selection. Further, time indicating data are inserted at 1/10th second intervals beginning from a zero point, and the beginning of a desired selection is generally accessed by detecting the time indicating data. In practice, however, each selection begins at some point which is several seconds away from the respective zero point. Thus, if the pickup device is located adjacent the zero point, a few seconds of silence, or dead air, occurs between the beginning of the reproduction operation and the actual reproduction of music. This dead air is undesirable when a digital audio disc is broadcast from a radio station.
Furthermore, certain prior art methods of reproducing a selected portion of a digital audio disc require a knowledge of the playing time of the selected portion before it can be reproduced.